This study is designed to test the hypothesis that taxotere can be safely administered to adolescents with relapsed leukemia as a 1 hour infusion. The following specific aims will be addressed in this Phase I study to test this hypothesis: 1) to determine the maximum tolerated dose and the dose-limiting capacity of taxotere given as a 1 hour infusion to children with refractory malignancies; 2) to determine the incidence and severity of other toxicities of taxotere administered as a 1 hour intravenous infusion; 3) to determine a safe and tolerable dose for taxotere, as a 1 hour intravenous infusion, to be used in phase II trials; 4) the pharmacokinetics of taxotere administered to children as a 1 hour intravenous infusion; and 5) to assess a safe and tolerable dose for taxotere, as a 1 hour intravenous infusion, when administered with G-CSF.